Wyoming health officials are warning residents and summer travelers of possible measles exposure after confirming a case involving an unvaccinated adult in Teton County, with exposure sites identified in Grand Teton National Park and Jackson.
The Wyoming Department of Health said potential exposures occurred between June 17 and June 25 at restaurants in Colter Bay Village on June 17 and 18, the Colter Bay convenience store on June 20, and the Target store in Jackson on June 25, WyoFile.com reported. The public notice is intended to identify people who may have been exposed, not to indicate an outbreak.
The warning comes as large numbers of summer tourists visit the region.
"We are asking people who may have been exposed to watch for measles symptoms for 21 days past the exposure date and consider avoiding crowded public places and high-risk settings such as daycare centers," said Wyoming State Health Officer Dr. Alexia Harrist.
The health department urged people who have not been vaccinated against measles, mumps, and rubella to watch closely for symptoms.
The case is Wyoming's second confirmed measles infection of 2026. The state's first case this year was confirmed in May involving an adult whose vaccination status could not be confirmed.
Wyoming had gone 15 years without a confirmed measles case before reporting infections again in 2025.
Wyoming reported 14 measles cases in 2025, with most involving unvaccinated children and adults.
The Centers for Disease Control and Prevention recommends a 95% vaccination rate to maintain community immunity against measles.
CDC data cited by WyoFile showed 93.6% of Wyoming kindergarten students had completed the MMR vaccination series in 2025.
The rate is higher than neighboring Colorado, Utah, and Montana but remains below Wyoming's vaccination levels from more than a decade ago.
Measles is highly contagious and can lead to serious complications, including pneumonia and brain swelling.
According to the CDC, the United States has recorded 30 new measles outbreaks in 2026. The agency said 93% of the nation's 2,134 confirmed cases have been linked to outbreaks, including 629 cases tied to outbreaks that began this year and 1,353 associated with outbreaks that started in 2025.